Managers at Ford Motor Co.'s Michigan Truck plant in Wayne say workers are spending too much time in the bathroom, an internal memo says.

So supervisors will start collecting weekly data to monitor rest room breaks, according to the memo, distributed to workers at the plant this week.

The factory's 3,500 hourly workers are allowed 48 minutes per shift for such breaks.

Ford says workers taking longer breaks are slowing down production of the Ford Expedition and Lincoln Navigator sport utility vehicles built at the plant, The Detroit News reported Thursday.

"In today's competitive environment, it is important that Michigan Truck plant immediately address this concern to avoid the risks associated with safety, quality, delivery, cost and morale," the memo says.

The union, of course, is pissed off:

Some managers get "petty" during tough times, said Jody Caruana, a committee member for the United Auto Workers Local 900 that represents plant workers.

"It's an excuse by upper management to gloss over some of the real problems we have out here," Caruana said. "Is this causing a quality or productivity problem? No. If someone is not on the job, you can bet someone else is who knows what they are doing."

UPDATE: Chrysler, which doesn't seem to be having as many problems lately as Ford or GM, seems to think its workers should be treated as adults:

Chrysler on bathrooms: Take your timeCar maker says it has no plans to follow Ford plant in monitoring restroom breaks.

NEW YORK (CNN/Money) - If assembly-line workers at Chrysler Group plants gotta go to the bathroom, they can take their time, according to a Web posting by a top executive.

Jason Vines, the automaker's vice president of communications, says on his corporate Weblog that the North American division of DaimlerChrysler (Research) doesn't plan to monitor workers' bathroom breaks.

The statement is an apparent response to the Detroit News disclosure last week that trips to the lavatory are being monitored at a Ford Motor (Research) plant in Wayne, Mich., in an effort to cut costs at the beleaguered automaker.

"We're not gonna use a stopwatch, turning a natural function into an Olympic sport," said Vines on his blog. "That ... would just be ... well ... too anal."